What is biometrics?
It is the science of identifying individuals by their unique biological
characteristics. The best known and earliest example is fingerprints,
used by ancient Babylonians as a signature and by police since the turn
of the 20th century to identify criminals.

But in the last decade there has been a boom in more advanced
biometric technology, allowing people to be identified, and sometimes
remotely tracked, by their voices, the irises of their eyes, the
geometry of their faces, and the way they walk.

The FBI is consolidating existing fingerprint records, mug shots, and
other biometric data on more than 100 million Americans into a single
$1.2 billion database. When it is completed, in 2014, police across the
country will theoretically be able to instantly check a suspect against
that vast and growing array of data.

Law-enforcement officials are enthusiastic about this growing power,
while civil libertarians are aghast. "A society in which everyone's
actions are tracked is not, in principle, free," said William Abernathy
and Lee Tien of the Electronic Frontier Foundation. "It may be a livable
society, but would not be our society."

How did the boom come
about? The age of terrorism has created enormous interest in — and
lowered resistance to — identifying and tracking individuals in a very
precise way. "Biometrics represent what terrorists fear most: an increased likelihood of getting caught," said Homeland Security spokesman Russ Knocke.
Since 2002, the government has fingerprinted all foreign visitors to
the U.S. at airports and borders, collecting approximately 300,000
prints per day. In Afghanistan and Iraq, U.S. forces have gathered iris
data from 5.5 million people, to identify suspected insurgents and
prevent infiltration of military bases. Fueled by the growth of iris
scans in particular, the global biometrics industry in 2013 has revenues
of $10 billion — and is expected to double that in five years.

How
do iris scans work? Every person has unique patterns within the colored
part of his or her eye. A device scans your iris and compares it with
photos of irises on record, identifying people with accuracy rates of 90
to 99 percent, depending on the conditions and system used. Iris
scanners are now widely used on military bases, in federal agencies, and
at border crossings and airports.

An improved iris scan version can remotely assess up to 50 people per
minute, making it possible to scan crowds for known criminals or
terrorists whose iris patterns are on file. Facial recognition
technology, which identifies people through such geometric relationships
as the distance between their eyes, has also come a long way. The
technology is still only about 92 percent accurate, but "the error rate
halves every two years," said facial recognition expert Jonathon
Phillips.

What other biometrics are there? The U.S. military is
already using radar that can detect the unique rhythm of a person's
heartbeat from a distance, and even through walls. That technology is
being developed for use in urban battlefields, but may one day become a
law-enforcement tool.

A person's gait, too, is completely individual, and the technology to
recognize it has advanced to the point where a person can be identified
by hacking into the sensor that tracks the movement of the cellphone in
his or her pocket. "Because it does not require any special devices,
the gait biometrics of a subject can even be captured without him or her
knowing," said Carnegie Mellon University biometrician Marios Savvides.

What
are the privacy implications? Civil liberties groups warn that if these
technologies are not restrained by law, they could be used in truly
Orwellian ways. No laws currently limit data collection from biometric
technology or the sharing of that data among federal agencies.

Law-enforcement officials can use driver's license photos to identify
or hunt for suspects, for example; the government or private companies
could collect a person's biometric data without his consent and use it
to track his movements. "That has enormous implications, not just for
security but also for American society," said Chris Calabrese of the
American Civil Liberties Union.

Is there any turning back? Probably not, especially now that private companies are embracing biometrics.
Already, TD Bank and Barclays Bank are using voice recognition
technology to verify account holders. In the not-too-distant future,
we'll be able to start our cars with our fingerprints, use facial
recognition or iris scans instead of passwords on smartphones and other
electronic devices, and have doctors check our medical records by
scanning our faces.

These uses of biometrics will provide convenience and efficiency, but
at a steep price in privacy. Iris technology that reads our eye
movements, for example, will be able to determine what we look at in
stores — then use that data to create highly personalized advertising
aimed at what we've displayed interest in. "For companies and
governments," said the ACLU's Jay Stanley, "the incentives associated
with biometrics all point the other way from privacy."

Here in
the U.S., proposals to put biometric data on Social Security cards have
faltered because of concern among civil libertarians and conservatives
over government overreach. But in much of the developing world, the
concept of personal privacy carries less legal and cultural weight, and
there a biometric revolution is taking place, with some 160 massive
data-gathering projects underway.

Until the 21st century, more than a third of people in developing
countries were not registered in any way at birth, making it hard for
them to open bank accounts, get government benefits, or vote. Biometric
IDs could change that.

India is taking the fingerprints and iris scans of all 1.2 billion of
its citizens. Nandan Nilekani, the founder of outsourcing firm Infosys
and the project's leader, says being identified will allow India's
largely anonymous masses to claim services to which they're entitled
under the law, rather than being forced to bribe bureaucrats. "Unique
identification is a means to empowerment," he said.